The Significance of the Numbers of Mast Cells in the Evaluation of Skin-Biopsy Specimens from Cats with Inflammatory Dermatoses

Abstract

It has often been stated that large numbers of mast cells in skin-biopsy specimens from cats are consistent with allergic dermatitis. We performed a retrospective study of hematoxylin and eosin (H&E)-stained skin-biopsy specimens from cats with allergic (n=143) and nonallergic (n=228) inflammatory skin diseases. All specimens had been submitted to the Section of Anatomic Pathology of the Cornell University College of Veterinary Medicine between 1978 and 2010. We found that dermal mast cell numbers are not significantly different between allergic and nonallergic cats. We also found that mast cell numbers are higher in the superficial than the deep dermis in cats with allergic and nonallergic skin diseases. In normal cat skin (n=31), mast cell numbers in the superficial dermis were higher in toluidine blue-stained specimens than in H&E-stained specimens.